One of the major research goals in schizophrenia has addressed the need to reduce the heterogeneity common to the illness presentation, course and outcome. This focus has led to a search for schizophrenic subtypes. Subtyping of symptoms has been considered essential to offering information regarding the etiological, prognostic and therapeutic aspects of schizophrenia and in validation of the definition and conceptualization of the disorder. Current interest in the existence of multiple illness domains, which occur in various combinations across the illness course for individuals with schizppherenia, identifies the need for further exploration of the symptoms commonly included in the Positive/Negative symptom groups, their temporal patterns and the interaction between the symptoms, the domains and other key variables. The broad objective of this study is to examine the changing patterns in the temporal course of schizophrenic symptoms over a three year period of the disorder. The specific aims are to (1) model and describe the longitudinal patterns of change in symptoms common to the Positive/negative symptom groups (2) to determine if individuals in the sample differ qualitatively with regard to severity of symptom ratings and rates and direction of change (3) to determine if the variation in the symptom patterns differ systematically due to gender, phase of illness, psychosocial treatment and diagnosis. The study sample consists of 172 individuals diagnosed with schizophrenia or schizoaffective disorder who participated in a longitudinal quasi-experimental investigation of three different models of community based care . Symptom data was collected every six months using the BPRS, CAF and QLS. Statistical analyses will be conducted using Hierarchical Linear Modeling (HLM) this method provides a mechanisms for the longitudinal modeling of symptoms, examination of individual subject variation, and testing to determine if covariates are responsible for any of the variation in symptom patterns. Findings from this study offer a potential contribution to clinical knowledge regarding the temporal and subtype variation in symptom patterns and a methodological/statistical application relevant to future longitudinal research efforts aimed at examination of individual differences in dynamic, changing variables.